Automotive accessory having an electromagnet pulley assist mechanism equipped with circumferentially spaced teeth nested with a conductive body

ABSTRACT

An electrically and mechanically driven automotive accessory including a housing, an electric motor, a pulley, and a pulley assist mechanism. The electric motor comprises a stator assembly that is mounted to the housing and a rotating assembly that is mounted to a shaft. The electric motor creates a primary torque flow path that drives rotation of the rotating assembly relative to the stator assembly. The pulley is rotatable relative to the shaft and the rotating assembly. The pulley assist mechanism includes a plurality of circumferentially spaced teeth nested with a conductive body, a rotor body fixedly mounted to the shaft, and an electromagnet that is configured to induce a magnetic field between the circumferentially spaced teeth, the rotor body, and the pulley, which creates a secondary torque flow path between the pulley and the rotor body.

FIELD

The subject disclosure is generally directed to electrically andmechanically driven automotive accessories, including withoutlimitation, electrically and mechanically driven automotive pumps. Thesubject disclosure is also directed to methods of operating the same.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Automobiles typically include a variety of different automotiveaccessories that are either driven by electric motors or drivenmechanically off of the engine, and more particularly, off of anaccessory belt that is driven by the crankshaft of the engine. Examplesinclude pumps for pumping coolant, oil, transmission fluid, and fuel.Further examples include pumps for pumping engine intake air, which aresometimes referred to as compressors. Mechanically driven automotiveaccessories suffer from several disadvantages, chief among them beingthat they cannot be driven when the engine is not running. In addition,the rotational speed and thus the output of mechanically drivenautomotive accessories is dependent upon engine speed. Therefore, thespeed and output of typical mechanically driven automotive accessoriescannot be controlled independently of the engine speed.

Electrically driven automotive accessories solve the problems associatedwith typical mechanically driven automotive accessories, but carry withthem their own disadvantages. Most automotive electrical systemsgenerate and run on 12 volts (V) direct current (DC). There arepractical limits on the power of electric motors that can be run off of12 volts (V) direct current (DC) because once a certain power level isexceeded, the heat generated by the electric motor becomes difficult tomanage and can cause the electronics to overheat. This makes itdifficult to provide an electrically powered automotive accessorycapable of delivering an output of 1 kilowatt (kW) while still utilizinga power supply that runs off 12 volts (V) direct current (DC).Accordingly, automobile manufacturers must settle for less powerfulelectrically driven automotive accessories if they want an automobileaccessory that can be driven independently of engine speed and when theengine is not running.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In accordance with one aspect of the present disclosure, an electricallyand mechanically driven automotive accessory is provided. Theelectrically and mechanically driven automotive accessory includes ahousing, an electric motor configured to rotationally drive a shaft, anda pulley that is rotatable relative to both the electric motor and theshaft. The shaft is rotatably supported in the housing and extends alonga longitudinal axis between an input end and an output end. The electricmotor comprises a stator assembly and a rotating assembly. When theelectric motor is activated, the electric motor creates a primary torqueflow path that drives rotation of the rotating assembly relative to thestator assembly. The stator assembly is fixedly mounted to the housing.The rotating assembly is fixedly mounted to the shaft such that therotating assembly rotates with the shaft. The pulley is rotatablysupported on the input end of the shaft such that the pulley isrotatable relative to the shaft and the rotating assembly. Theelectrically and mechanically driven automotive accessory has a pulleyassist mechanism. The pulley assist mechanism includes an electromagnet,a plurality of circumferentially spaced teeth that are nested with aconductive body, and a rotor body that is fixedly mounted to the shaft.When the electromagnet is activated, a magnetic coupling is formed thatcreates a secondary torque flow path between the pulley and the rotorbody due to the magnetic field generated in the pulley, thecircumferentially spaced teeth, and the rotor body by the electromagnet.

In accordance with another aspect of the present disclosure, a method ofoperating the electrically and mechanically driven automotive accessorydescribed above is provided. The method includes the step of applyingelectricity to electrical windings of the stator assembly to generate anelectromagnetic field and a primary torque flow path that rotationallydrives the rotating assembly and the shaft. The method also includes thestep of rotationally driving the pulley, which is rotatably supported ona pulley bearing assembly. The method further comprises the step ofactivating the pulley assist mechanism by applying electricity to theelectromagnet of the pulley assist mechanism to induce a magnetic fieldbetween the pulley, the circumferentially spaced teeth, and the rotorbody to create a secondary torque flow path between the pulley and therotor body.

The secondary torque flow path provided by the pulley assist mechanismadds to the primary torque flow path produced by the electric motor,which allows the shaft to be driven at a higher rotational speed thanwould otherwise be possible by utilizing only the primary torque flowpath. As a result, the electrically and mechanically driven automotiveaccessory described herein can generate 1.7-1.8 kilowatt (kW) of pumpingpower, or more, utilizing an electric motor that runs off of 12 volts(V) direct current (DC). Additionally, the electric current supplied tothe electrical windings of the stator assembly can be reduced for anygiven rotational speed when the electromagnet of the pulley assistmechanism is activated. This means that higher rotational speeds andpower output are possible while retaining an electric motor that runs ona 12 volt power supply without overheating. The pulley assist mechanismalso allows the electric motor to be downsized because peak demandusually coincides with high engine speeds, where the rotational speed ofthe pulley is high and the pulley assist mechanism is most effective(i.e., when the pulley assist mechanism can provide the largest increasein rotational speed to the rotating assembly).

Unlike mechanically driven automotive accessories, the electrically andmechanically driven automotive accessory described herein can be drivenby just the electric motor when the engine of the vehicle is notrunning. Additionally, the rotational speed of the shaft is fullyvariable and can be controlled independently of the speed of the engine.The electric current applied to the electromagnet of the pulley assistmechanism can be controlled to vary the degree of magnetic couplingbetween the pulley and the rotor body. As a result, the amount of torquetransfer between the pulley and the rotor body through the secondarytorque flow path can be adjusted to control the rotational speed of theshaft as well as the amount of mechanical drag the pulley places on theengine of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present disclosure will be readily appreciated,as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a side perspective view of an electrically and mechanicallydriven automotive accessory that has been constructed in accordance withthe teachings of the present disclosure;

FIG. 2 is an exploded perspective view of the electrically andmechanically driven automotive accessory illustrated in FIG. 1 ;

FIG. 3 is a side section view of the electrically and mechanicallydriven automotive accessory illustrated in FIG. 1 ;

FIG. 4 is a side perspective view of an exemplary rotating assembly ofthe electrically and mechanically driven automotive accessoryillustrated in FIG. 1 ;

FIG. 5 is another side perspective view of the rotating assemblyillustrated in FIG. 4 , where the internal components of the rotatingassembly are shown in dashed lines;

FIG. 6 is a side cross-sectional view of the electrically andmechanically driven automotive accessory illustrated in FIG. 1 ;

FIG. 7 is a side perspective view of another electrically andmechanically driven automotive accessory that has been constructed inaccordance with the teachings of the present disclosure;

FIG. 8 is an exploded perspective view of the electrically andmechanically driven automotive accessory illustrated in FIG. 7 ;

FIG. 9 is a side section view of the electrically and mechanicallydriven automotive accessory illustrated in FIG. 7 ;

FIG. 10 is a side perspective view of the electrically and mechanicallydriven automotive accessory illustrated in FIG. 7 ;

FIG. 11 is another side perspective view of the electrically andmechanically driven automotive accessory illustrated in FIG. 7 , wherethe internal components of the electrically and mechanically drivenautomotive accessory are shown in dashed lines;

FIG. 12 is a side cross-sectional view of the electrically andmechanically driven automotive accessory illustrated in FIG. 7 ;

FIG. 13 is an exploded perspective view of another electrically andmechanically driven automotive accessory that has been constructed inaccordance with the teachings of the present disclosure; and

FIG. 14 is a side cross-sectional view of the electrically andmechanically driven automotive accessory illustrated in FIG. 13 .

DETAILED DESCRIPTION

Referring to the Figures, wherein like numerals indicate correspondingparts throughout the several views, three electrically and mechanicallydriven automotive accessories 20, 20′, 20″ are disclosed.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the FIGS. is turned over,elements described as “below” or “beneath” other elements or featureswould then be oriented “above” the other elements or features. Thus, theexample term “below” can encompass both an orientation of above andbelow. The device may be otherwise oriented (rotated 90 degrees or atother orientations) and the spatially relative descriptors used hereininterpreted accordingly.

With reference to FIGS. 1-6 , the electrically and mechanically drivenautomotive accessory 20 disclosed herein includes a housing 22, anelectric motor 24 configured to rotationally drive a shaft 26, and apulley 28 that is rotatable relative to both the electric motor 24 andthe shaft 26. The pulley 28 may include a belt contact surface 29 inconfigurations where the pulley 28 is configured to be rotationallydriven by a belt (not shown), such as a rubber accessory belt, that isdriven by an engine (not shown). The belt contact surface 29 of thepulley 28 engages the belt and may optionally include a channel withgrooves. Alternatively, the pulley 28 may be rotationally driven by agear or a shaft that is powered by the engine. The engine may be,without limitation, an internal combustion engine powering a vehicle(not shown). As will be explained in greater detail below, theelectrically and mechanically driven automotive accessory 20 includes apulley assist mechanism 30 that utilizes electromagnetism to transfertorque from the pulley 28 to the shaft 26 to provide a torque assist(i.e., a mechanical boost) to the electric motor 24 under certainoperating conditions.

In the embodiment shown in FIGS. 1-6 , the housing 22 includes a tubularportion 32 and a flange portion 34 that mate with one another and givethe housing 22 a split, clam-shell like arrangement. The tubular portion32 extends annularly about a longitudinal axis 36 between a firsthousing end 38 and a second housing end 40. The flange portion 34 matesto the tubular portion 32 at the second housing end 40. One of moreseals 41 are disposed between the tubular portion 32 and the flangeportion 34 of the housing 22. The shaft 26 of the electrically andmechanically driven automotive accessory 20 is received in the tubularportion 32 of the housing 22. The shaft 26 extends along thelongitudinal axis 36 between an input end 42 and an output end 44. Itshould therefore be appreciated that the term “longitudinal” used hereindescribes directions and structures that are parallel or co-axial to thelongitudinal axis 36, that the term “radial” as used herein describesdirections and structures that extend radially towards and away from thelongitudinal axis 36 at a transverse angle relative to the longitudinalaxis 36, and that the term “circumferentially spaced” as used hereindescribed structures that are spaced apart along different radians(degrees) relative to the longitudinal axis 36 like the numbers on aclock.

The shaft 26 is longer than the tubular portion 32 of the housing 22such that the input end 42 of the shaft 26 extends out from the firsthousing end 38 and the output end 44 of the shaft 26 extends out fromthe second housing end 40. The shaft 26 is rotatably supported in thetubular portion 32 of the housing 22 by a shaft bearing assembly 46.Although other configurations are possible, the shaft bearing assembly46 may have an integrated shaft bearing arrangement with an outer sleeve48 that is press fit into the tubular portion 32 of the housing 22 andtwo longitudinally spaced ball bearing packs 50 that are positionedradially between the shaft 26 and the outer sleeve 48. During operation,the housing 22 may remain stationary while the shaft bearing assembly 46allows the shaft 26 to rotate co-axially about the longitudinal axis 36and relative to the housing 22.

Both the housing 22 and the shaft 26 may be made of a wide variety ofdifferent materials, including without limitation, various metals.Optionally, a shaft seal 52, extending annularly about the shaft 26, maybe provided adjacent to the output end 44 of the shaft 26. In theillustrated example, the shaft seal 52 is made of a resilient materialand is positioned radially between the shaft 26 and the housing 22. Theshaft seal 52 in this example is fixed to the housing 22 such that theshaft 26 rotates relative to the shaft seal 52; however, in analternative embodiment, the shaft seal 52 may be fixed to the shaft 26such that it rotates with the shaft 26 and relative to the stationaryhousing 22.

In the illustrated example, the electrically and mechanically drivenautomotive accessory 20 is a fluid pump, such as a pump for pumpingliquid. Such liquids may include, but are not limited to, water,coolant, oil, transmission fluid, or fuel. In accordance with thisembodiment, the electrically and mechanically driven automotiveaccessory 20 includes an impeller 54 that is fixedly mounted to theoutput end 44 of the shaft 26. The impeller 54 includes one or morevanes 56. The impeller 54 can be made of a wide range of materials,including without limitation, injection molded plastic. Duringoperation, the impeller 54 rotates with the shaft 26, which causes thevanes 56 of the impeller 54 to pump liquid through the fluid pump.However, it should be appreciated that the scope of the presentdisclosure is not limited to liquid pumps. For example, the electricallyand mechanically driven automotive accessory 20 may be configured as anair pump (also known as an air compressor). In other non-limitingexamples, the electrically and mechanically driven automotive accessory20 could also be other automotive accessories that are typically drivenby an electric motor, an accessory belt off the engine, the serpentinebelt of the engine, the crankshaft of the engine, or a camshaft of theengine.

The electric motor 24 of the electrically and mechanically drivenautomotive accessory 20 is configured to create a primary torque flowpath that drives rotation of the shaft 26 when the electric motor 24 isactivated. Although other configurations are possible, the electricmotor 24 in the illustrated embodiment comprises a stator assembly 58and a rotating assembly 60. The rotating assembly 60 is rotatablerelative to the stator assembly 58 about the longitudinal axis 36. Thestator assembly 58 is fixedly mounted on the tubular portion 32 of thehousing 22 and therefore remains stationary during operation. Theelectrically and mechanically driven automotive accessory 20 includes astationary backing member 62 and the stator assembly 58 includes aplurality of stator plates 64, all of which are fixedly mounted on thetubular portion 32 of the housing 22. The stator plates 64 are stackedtogether and include a plurality of arms 66 that support electricalwindings 68. Although other configurations are possible, in theillustrated embodiment, the stator plates 64 are made of metal and theelectrical windings 68 are made of copper wire. The stator plates 64 andthe electrical windings 68 may also be encased in a resin or a plasticto protect them from corrosion/oxidation, vibration, contaminants, andimpact damage and to structurally unitize the stator assembly 58.

The stationary backing member 62 includes a plurality of spokes 70 thatare fixedly mounted to the tubular portion 32 of the housing 22 via apress fit and an annular portion 72 that is positioned radially outwardof the tubular portion 32 of the housing 22. The plurality of spokes 70extend radially outwardly from the tubular potion 32 of the housing 22to the annular portion 72. A spacer 74 is positioned on the tubularportion 32 of the housing 22 between the stationary backing member 62and the stator plates 64 to maintain the longitudinal spacing of thesecomponents. The rotating assembly 60 includes a rotating backing member80. The rotating backing member 80 extends circumferentially about atleast a portion of the stator assembly 58. It should be appreciated thatthe words “stationary” and “rotating” used to describe the backingmembers 62, 80 are merely used for labelling purposes and refer to therelative motion between these two components when the electric motor 24is running.

Permanent magnets 82 are fixedly mounted to the rotating backing member80 and are spaced radially outward of the stator plates 64. Whenelectricity (i.e., electric current) is applied to the electricalwindings 68 of the stator assembly 58, an electromagnetic field iscreated that interacts with the magnetic field of the permanent magnets82, which causes the rotating backing member 80 to rotate. Althoughother configurations are possible, the stationary backing member 62 andthe rotating backing member 80 may be made of a ferrous metal materialand the permanent magnets 82 of the rotating assembly 60 may be made ofa ferritic material or rare earth materials, such as samarium cobalt(SmCo) or neodymium-iron boron (NdFeB), and may be glued to an insidesurface 84 of the rotating backing member 80.

The pulley 28 is rotatably supported on the input end 42 of the shaft 26such that the pulley 28 is rotatable relative to the shaft 26 and therotating assembly 60. In the illustrated example, the pulley 28 has ahub portion 86, a pulley wall 88, and two annular rims 90. The pulleywall 88 extends radially outwardly from the hub portion 86 and the beltcontact surface 29 is positioned between the two annular rims 90. Thebelt contact surface 29 is configured to mate with (i.e., contact) thebelt (not shown), while the two annular rims 90 of the pulley 28 areconfigured to help prevent the belt from sliding/jumping off of thepulley 28. The pulley wall 88 may optionally include a plurality ofradially extending slots 92 to save weight. The pulley 28 is supportedby a pulley bearing assembly 96 that is positioned radially between theinput end 42 of the shaft 26 and the hub portion 86 of the pulley 28.Although other configurations are possible, in the illustratedembodiment, the pulley bearing assembly 96 includes an inner race 98that is press fit on the input end 42 of the shaft 26, an outer race 100that is press fit into the hub portion 86 of the pulley 28, and aplurality of ball bearings 102 that are positioned radially between theinner and outer races 98, 100. As a result, the pulley 28 can rotaterelative to the shaft 26 and the rotating assembly 60, which can rotateindependently of the pulley 28.

The pulley assist mechanism 30 includes an electromagnet 108 that issupported on the stationary backing member 62. More specifically, thestationary backing member 62 is a bobbin that supports the electromagnet108. For example, in the illustrated embodiment, the electromagnet 108is a wire coil 126 of copper wire that is wound about the stationarybacking member 62. The pulley assist mechanism 30 further includes aplurality of circumferentially spaced teeth 110 that are nested with aconductive body 111, a rotor body 112 that is fixedly mounted to theshaft 26, and a claw body 113 that is fixed with the pulley 28. Therotor body 112 rotatably couples the rotating backing member 80 to theshaft 26. As a result, the rotating backing member 80 and the rotor body112 always rotate at the same rotational speed as the shaft 26, whilethe claw body 113 always rotates at the same rotational speed as thepulley 28, which may be different than the rotational speed of the shaft26. In this embodiment of the pulley assist mechanism 30, both thecircumferentially spaced teeth 110 and the conductive body 111 are fixedto the rotor body 112. For example, as shown in FIGS. 4 and 5 , thecircumferentially spaced teeth 110 are integral with the rotor body 112while the conductive body 111 is press fit onto the rotor body 112,although other configurations may be possible.

The rotor body 112 includes a hub segment 130 that is press fit onto theshaft 26 and an annular segment 132 that is connected to the hub segment130 by radially extending spokes 134. The annular segment 132 has aring-like shape and includes an outer diameter face 135, an innerdiameter face 136 opposite the outer diameter face 135, a first sideface 138 that faces the pulley 28 and a second side face 140 oppositethe first side face 138. The plurality of circumferentially spaced teeth110 include a first set of teeth 110 a that extend lengthwise in aplurality of radial directions (i.e., in directions transverse to thelongitudinal axis 36) and a second set of teeth 110 b that extendlengthwise in a plurality of longitudinal directions (i.e., indirections parallel to the longitudinal axis 36). The first set of teeth110 a protrude longitudinally from the first side face 138 of the rotorbody 112 at a first height H1 and the second set of teeth 110 b protruderadially from the outer diameter face 135 of the rotor body 112 at asecond height H2. The circumferentially spaced teeth 110 extend througha plurality of openings 142 in the conductive body 111. Morespecifically, the plurality of openings 142 in the conductive body 111include a first set of openings 142 a that receive the first set ofteeth 110 a and a second set of openings 142 b that receive the secondset of teeth 110 b. As a result, the features of the conductive body 111nest with the features of the rotor body 112.

The claw body 113 is positioned between the pulley 28 and the rotor body112. The claw body 113 includes a radial portion 144 that extendsradially outwardly from the pulley bearing assembly 96 to a longitudinalportion 146. The claw body 113 is fixed with the pulley 28 by a pressfit such that the claw body 113 and the pulley 28 both rotate at thesame rotational speed. The claw body 113 includes a plurality ofcircumferentially spaced slots 148, which give the claw body 113 acage-like structure made up of a plurality of circumferentially spacedfingers. Each slot 148 is bi-axial and has a radial component 148 a thatis in plane with the radial portion 144 of the claw body 113 andtransverse to the longitudinal axis 36 and a longitudinal component 148b that is in plane with the longitudinal portion 146 of the claw body113 and parallel to and spaced from the longitudinal axis 36. The radialcomponent 148 a and longitudinal component 148 b of each slot 148 arecontiguous. Further, the radial component 148 a of each slot 148 isclosed at one end while the longitudinal component 148 b of each slot148 is open at one end.

The stationary backing member 62, the rotor body 112, the claw body 113,and the pulley 28 are all made of a magnetic material, such as a ferrousmetal material. As best seen in FIG. 6 , when electricity (i.e.,electric current) is applied to wire coil 126, the electromagnet 108 ofthe pulley assist mechanism 30 induces a magnetic loop 128 in thecircumferentially spaced teeth 110 of the rotor body 112 and in portionsof the stationary backing member 62, the pulley 28, the rotor body 112,and the claw body 113. When the electromagnet 108 of the pulley assistmechanism 30 is deactivated (i.e., de-energized), the magnetic couplingbetween the pulley 28 and the rotor body 112 ends. As a result, there isno torque transfer between the pulley 28 and the rotor body 112 when theelectromagnet 108 is deactivated. However, when the electromagnet 108 ofthe pulley assist mechanism 30 is activated (i.e., energized), themagnetic field induced between the pulley 28, the claw body 113, and thecircumferentially spaced teeth 110 of the rotor body 112 results intorque transfer between the pulley 28 and the rotor body 112.

There are a number of predetermined tolerances (i.e., small gaps)between an outer edge 120 of the stationary backing member 62 and theinner diameter face 136 of the rotor body 112, between the radialportion 144 of the claw body 113 and the first set of teeth 110 a of therotor body 112, and between the longitudinal portion 146 of the clawbody 113 and the second set of teeth 110 b of the rotor body 112. Thesetolerances must be small enough to provide a relatively uninterruptedmagnetic loop 128 when the electromagnet 108 is activated, but largeenough to accommodate manufacturing tolerances and permit relativemotion between the rotor body 112 and the claw body 113 and relativemotion between the rotor body 112 and the stationary backing member 62.By way of example and without limitation, these predetermined tolerancesmay be 100-200 microns (μm) and preferably about 150 microns (μm).

The circumferentially spaced teeth 110 and the rotor body 112 are madeof a first material 150 while the conductive body 111 is made of asecond material 152. The first material 150 is ferromagnetic and has ahigher magnetic flux density than the second material 152. By way ofexample and without limitation, the first material 150 may be steel. Thesecond material 152 has a higher electrical conductivity than the firstmaterial 150. By way of example and without limitation, the secondmaterial 152 may be aluminum or copper. The claw body 113 is also madeof a ferromagnetic material, such as steel. This results in a structurewhere the circumferentially spaced teeth 110 of the rotor body 112 havea higher flux density while the conductive body 111 has a higherelectrical conductivity and less weight.

As explained above, when the electromagnet 108 is energized a magneticloop 128 is created that extends through the circumferentially spacedteeth 110 of the rotor body 112, the stationary backing member 62, thepulley 28, and the claw body 113. When the pulley 28 and the claw body113 rotate at a different speed than the rotor body 112 while theelectromagnet 108 is energized, the circumferentially spaced slots 148generate a change in magnetic flux in the circumferentially spaced teeth110 as the slots 148 pass over the teeth 110. This createsfluctuating/alternating magnetic poles (e.g., alternating di-poles) inthe circumferentially spaced teeth 110 and induces electric currents inthe conductive body 111. The induced electric currents in the conductivebody 111 flow around the circumferentially spaced teeth 110, creating asecondary magnetic field that resists relative motion between the rotorbody 112 and the pulley 28/claw body 113, which ultimately results intorque transfer and thus a secondary torque flow path between the pulley28 and the rotor body 112, which is connected to the shaft 26.

The magnetic coupling between the pulley 28 and the rotor body 112,requires relative motion between the pulley 28 and rotor body 112.Accordingly, there will always be some rotational slip between thepulley 28 and the rotor body 112, even when the electromagnet 108 isactivated. The electromagnet 108 of the pulley assist mechanism 30 isonly activated when the belt is driving the pulley 28 at a fasterrotational speed than the rotational speed that the rotating assembly 60is being driven at via the primary torque flow path produced by theelectric motor 24. When the electromagnet 108 is activated in suchconditions, the secondary torque flow path provided by the pulley assistmechanism 30 (i.e., the induced magnetic coupling between the pulley 28and the rotor body 112) adds to the primary torque flow path produced bythe electric motor 24, which allows the rotating assembly 60 andtherefore the shaft 26 to be driven at a higher rotational speed (i.e.,higher revolutions per minute/RPMs) than would be possible whenutilizing only the primary torque flow path. As a result, the fluid flowgenerated by the impeller 54 is increased. Additionally, the electriccurrent supplied to the electrical windings 68 of the stator assembly 58can be reduced for any given rotational speed when the electromagnet 108of the pulley assist mechanism 30 is activated.

In many cases, the pulley assist mechanism 30 also allows the electricmotor 24 to be downsized because peak pump demand usually coincides withhigh engine speeds, where the rotational speed of the pulley 28 is highand the pulley assist mechanism 30 is most effective (i.e., when thepulley assist mechanism 30 can provide the largest increase inrotational speed to the rotating assembly 60). As explained below, theelectromagnet 108 of the pulley assist mechanism 30 is deactivated whenthe primary torque flow path of the electric motor 24 is driving therotating assembly 60 at a rotational speed that is faster than therotational speed of the pulley 28. If the electromagnet 108 were notdeactivated during such conditions, the pulley assist mechanism 30 wouldslow the rotation of the rotating assembly 60 and act as a brake, whichwould be undesirable in most applications.

Unlike mechanically driven automotive accessories, the electrically andmechanically driven automotive accessory 20 described herein can bedriven by just the electric motor 24 when the engine of the vehicle isnot running. Additionally, the rotational speed of the shaft 26 is fullyvariable and can be controlled independently of the speed of the engine.The electric current applied to the wire coil 126 of the electromagnet108 can be controlled to vary the degree of magnetic coupling betweenthe pulley 28 and the rotor body 112. As a result, the amount of torquetransfer between the pulley 28 and the rotor body 112 can be adjusted tocontrol the rotational speed of the shaft 26 as well as the amount ofmechanical drag the pulley 28 places on the engine of the vehicle. Inother words, the amount of load the electrically and mechanically drivenautomotive accessory 20 places on the engine can be controlled in viewof the engine's speed, power output, fuel economy, and/or otheroperating parameters.

FIGS. 7-12 illustrate another electrically and mechanically drivenautomotive accessory 20′, with a pulley assist mechanism 30′ of analternative configuration that does not include the claw body 113 shownin FIGS. 1-6 . Many of the elements of the electrically and mechanicallydriven automotive accessory 20′ shown in FIGS. 7-12 are the same as theelements of the electrically and mechanically driven automotiveaccessory 20 shown in FIGS. 1-6 and therefore share the same referencenumbers, except that a prime (′) annotation has been appended after thereference numbers in FIGS. 7-12 .

The electrically and mechanically driven automotive accessory 20′ shownin FIGS. 7-12 includes a housing 22′ that has a tubular portion 32′ anda flange portion 34′. The tubular portion 32′ extends annularly about alongitudinal axis 36′ between a first housing end 38′ and a secondhousing end 40′. The flange portion 34′ attaches to the tubular portion32′ at the second housing end 40′. A shaft 26′ is received co-axiallyinside the tubular portion 32′ of the housing 22′. The shaft 26′ extendsalong the longitudinal axis 36′ between an input end 42′ and an outputend 44′.

The electrically and mechanically driven automotive accessory 20′includes an electric motor 24′ that again is configured to create aprimary torque flow path for driving rotation of the shaft 26′ when theelectric motor 24′ is activated. The electric motor 24′ illustrated inFIGS. 7-12 comprises a stator assembly 58′ and a rotating assembly 60′.The stator assembly 58′ is fixedly mounted inside the tubular portion32′ of the housing 22′ and therefore remains stationary duringoperation. The stator assembly 58′ includes a plurality of stator plates64′, which are fixedly mounted inside the tubular portion 32′ of thehousing 22′. The stator plates 64′ are stacked together, define acentral opening 65′, and include a plurality of arms 66′ that supportelectrical windings 68′.

The rotating assembly 60′ is positioned inside the central opening 65′of the stator assembly 58′, is rotatable relative to the stator assembly58′ about the longitudinal axis 36′, and includes a rotating backingmember 80′ that is fixedly mounted to the shaft 26′ such that therotating backing member 80′ rotates with the shaft 26′. It should beappreciated that the words “stationary” and “rotating” used to describethe backing members 62′, 80′ of the electric motor 24′ are merely usedfor labelling purposes and refer to the relative motion between thesetwo components when the electric motor 24′ is running. Permanent magnets82′ are fixedly mounted to the rotating backing member 80′ and arespaced radially inward of the stator plates 64′. When electricity (i.e.,electric current) is applied to the electrical windings 68′ of thestator assembly 58′, an electromagnetic field is created that interactswith the magnetic field of the permanent magnets 82′, which causes therotating backing member 80′ to rotate. The rotating backing member 80′is fixed to the shaft 26′ such that the electric motor 24′ rotationallydrives the shaft 26′ when electricity is applied to the electricalwindings 68′ of the stator assembly 58′.

The electrically and mechanically driven automotive accessory 20′includes a pulley 28′ with a pulley wall 88′ and the pulley assistmechanism 30′ includes an electromagnet 108′, a plurality ofcircumferentially spaced teeth 110′ that protrude longitudinally from aninboard face 94′ of the pulley wall 88′ at a first height H1′, aconductive body 111′, and a rotor body 112′. The electromagnet 108′includes a wire coil 126′ that is supported by a bobbin 127′. The bobbin127′ is fixedly attached to the stationary backing member 62′. Theplurality of circumferentially spaced teeth 110′ are nested with aconductive body 111′. The plurality of circumferentially spaced teeth110′ extend lengthwise in a plurality of radial directions (i.e., indirections transverse to the longitudinal axis 36′). Thecircumferentially spaced teeth 110′ extend into a plurality of openings142′ in the conductive body 111′. As a result, the features of theconductive body 111′ nest with the features of the pulley 28′. However,it should be appreciated that the openings 142′ in the conductive body111′ may or may not extend entirely through the conductive body 111′ andtherefore may be open on one side and closed on the other. Both thecircumferentially spaced teeth 110′ and the conductive body 111′ arefixed to the pulley 28′. For example, as shown in FIGS. 7-12 , thecircumferentially spaced teeth 110′ are integral with the pulley wall88′ and the conductive body 111′ is press fit onto the pulley 28′ overthe teeth 110′.

The pulley assist mechanism 30′ also includes a rotor body 112′ that isfixedly mounted to the shaft 26′. As a result, the rotor body 112′always rotates at the same rotational speed as the shaft 26′ andtherefore the rotating assembly 60′ of the electric motor 24′, while theconductive body 111′ always rotates at the same rotational speed as thepulley 28′, which may be different than the rotational speed of theshaft 26′ and the rotating assembly 60′ of the electric motor 24′. Therotor body 112′ is positioned between the pulley 28′ and a stationarybacking member 62′, which is fixedly mounted to the tubular portion 32′at the first housing end 38′. The rotor body 112′ includes a radialportion 144′ that extends radially outwardly from the shaft 26 to alongitudinal portion 146′. The radial portion 144′ of the rotor body112′ includes a first side face 138′ that faces the pulley 28′ and asecond side face 140′ opposite the first side face 138′. The rotor body112′ includes a plurality of circumferentially spaced ribs 148′ thatprotrude longitudinally from first side face 138′ of the rotor body 112′at a second height H2′ and extend lengthwise in a plurality of radialdirections (i.e., in directions transverse to the longitudinal axis36′).

As best seen in FIG. 12 , when electricity (i.e., electric current) isapplied to wire coil 126′, an electromagnet 108′ of the pulley assistmechanism 30′ induces a magnetic loop 128′ in the circumferentiallyspaced teeth 110′ and in portions of the stationary backing member 62′,the pulley 28′, the circumferentially spaced ribs 148′, and the rotorbody 112′. When the electromagnet 108′ of the pulley assist mechanism30′ is deactivated (i.e., de-energized), the magnetic coupling betweenthe pulley 28′ and the rotor body 112′ ends. As a result, there is notorque transfer between the pulley 28′ and the rotor body 112′ when theelectromagnet 108′ is deactivated. However, when the electromagnet 108′of the pulley assist mechanism 30′ is activated (i.e., energized), themagnetic field induced between the pulley 28′ and the rotor body 112′results in torque transfer between the pulley 28′ and the rotor body112′.

There are a number of predetermined tolerances (i.e., small gaps)between an outer edge 120′ of the stationary backing member 62′ and thepulley 28′, between the second side face 140′ of the rotor body 112′ andthe stationary backing member 62′, and between the circumferentiallyspaced teeth 110′ of the pulley 28′ and the circumferentially spacedribs 148′ of the rotor body 112′. These tolerances must be small enoughto provide a relatively uninterrupted magnetic loop 128′ when theelectromagnet 108′ is activated, but large enough to accommodatemanufacturing tolerances and permit relative motion between the rotorbody 112′ and the pulley 28′ and relative motion between the rotor body112′ and the stationary backing member 62′. By way of example andwithout limitation, these predetermined tolerances may be 100-200microns (μm) and preferably about 150 microns (μm).

The circumferentially spaced teeth 110′ and the pulley 28′ are made of afirst material 150′ while the conductive body 111′ is made of a secondmaterial 152′. The first material 150′ is ferromagnetic and has a highermagnetic flux density than the second material 152′. By way of exampleand without limitation, the first material 150′ may be steel. The secondmaterial 152′ has a higher electrical conductivity than the firstmaterial 150′. By way of example and without limitation, the secondmaterial 152′ may be aluminum or copper. The rotor body 112′ and thecircumferentially spaced ribs 148′ are also made of a ferromagneticmaterial, such as steel. This results in a structure where thecircumferentially spaced teeth 110′ of the pulley 28′ have a higher fluxdensity while the conductive body 111′ has a higher electricalconductivity and less weight.

When the pulley 28′ rotates at a different speed than the rotor body112′ while the electromagnet 108′ is energized, the circumferentiallyspaced ribs 148′ generate a change in magnetic flux in thecircumferentially spaced teeth 110′ as the ribs 148′ pass over the teeth110′. This creates fluctuating/alternating magnetic poles (e.g.,alternating di-poles) in the circumferentially spaced teeth 110′ andinduces electric currents in the conductive body 111′. The inducedelectric currents in the conductive body 111′ flow around thecircumferentially spaced teeth 110′, creating a secondary magnetic fieldthat resists relative motion between the rotor body 112′ and the pulley28′, which ultimately results in torque transfer and thus a secondarytorque flow path between the pulley 28′ and the rotor body 112′, whichis connected to the shaft 26′.

FIGS. 13 and 14 illustrate another electrically and mechanically drivenautomotive accessory 20″, with a pulley assist mechanism 30″ of analternative configuration that again does not include the claw body 113shown in FIGS. 1-6 . Many of the elements of the electrically andmechanically driven automotive accessory 20″ shown in FIGS. 7-12 are thesame as the elements of the electrically and mechanically drivenautomotive accessory 20′ shown in FIGS. 7-12 and therefore share thesame reference numbers, except that a double prime (″) annotation hasbeen appended after the reference numbers in FIGS. 13 and 14 .

In the arrangement shown in FIGS. 13 and 14 , the pulley assistmechanism 30″ is nearly identical to the pulley assist mechanism 30′shown in FIGS. 7-12 , except that the pulley assist mechanism 30″ shownin FIGS. 13 and 14 contains a conductive body 111″ that is fixed torotor body 112″ instead of pulley 28″. As a result, the pulley assistmechanism 30″ includes a plurality of circumferentially spaced teeth110″ that protrude longitudinally from a first side face 138″ of therotor body 112″ at a first height H1 “and a plurality ofcircumferentially spaced ribs 148” protrude longitudinally from aninboard face 94″ of the pulley wall 88″ at a second height H2″. Thecircumferentially spaced teeth 110″ extend through a plurality ofopenings 142″ in the conductive body 111″. As a result, the features ofthe conductive body 111″ nest with the features of the rotor body 112″.Both the circumferentially spaced teeth 110″ and the conductive body111″ are fixed to the rotor body 112″ instead of the pulley 28″ in thisembodiment. For example, as shown in FIGS. 13 and 14 , thecircumferentially spaced teeth 110″ are integral with the rotor body112″ and the conductive body 111″ is press fit onto the rotor body 112″over the teeth 110″. Notwithstanding these structural differences, thepulley assist mechanism 30″ shown in FIGS. 13 and 14 operates the sameway as the pulley assist mechanism 30′ shown in FIGS. 7-12 .

The electrically and mechanically driven automotive accessories 20, 20′,20″ described above can be controlled according to the method ofoperation set forth below. The method includes the step of applyingelectricity to the electrical windings 68, 68′, 68″ of the statorassembly 58, 58′, 58″ to generate an electromagnetic field and a primarytorque flow path that rotationally drives the rotating assembly 60, 60′,60″, and thus, the shaft 26, 26′, 26″. The method also includes the stepof rotationally driving the pulley 28, 28′, 28″, which is rotatablysupported on the pulley bearing assembly 96, 96′, 96″. The methodproceeds with the steps of detecting a first rotational speed of therotating assembly 60, 60′, 60″ and/or the shaft 26, 26′, 26″ anddetecting a second rotational speed of the pulley 28, 28′, 28″. Theelectrically and mechanically driven automotive accessories 20, 20′, 20″may optionally include one or more sensors (not shown) that areconfigured to measure/read the first rotational speed of the rotatingassembly 60, 60′, 60″ and/or the shaft 26, 26′, 26″ and the secondrotational speed of the pulley 28, 28′, 28″. Alternately, the firstrotational speed of the rotating assembly 60, 60′, 60″ and/or the shaft26, 26′, 26″ and the second rotational speed of the pulley 28, 28′, 28″can be determined based on the electric and magnetic fields (EMF) of theelectric motor 24, 24′, 24″. The method further includes the step ofactivating the pulley assist mechanism 30, 30′, 30″ when the secondrotational speed (i.e., the rotational speed of the pulley 28, 28′, 28″)is greater than the first rotational speed (i.e., the rotational speedof the rotating assembly 60, 60′, 60″/shaft 26, 26′, 26″). This stepincludes applying electricity to the electromagnet 108, 108′, 108″ toinduce a magnetic field between the pulley 28, 28′, 28″, thecircumferentially spaced teeth 110, 110′, 110″, and the rotor body 112,112′, 112″ to create a secondary torque flow path between the pulley 28,28′, 28′″ and the rotor body 112, 112′, 112″. The step of activating thepulley assist mechanism 30, 30′, 30″ produces the magnetic loops 128,128′, 128″ described above, which extend around the electromagnet 108,108′, 108″ through the circumferentially spaced teeth 110, 110′, 110″and portions of the rotor body 112, 112′, 112″, the stationary backingmember 62, 62′, 62″, and the pulley 28, 28′, 28″. The method may alsoinclude the step of deactivating the pulley assist mechanism 30, 30′,30″ when the first rotational speed (i.e., the rotational speed of therotating assembly 60, 60′, 60″/shaft 26, 26′, 26″) is greater than thesecond rotational speed (i.e., the rotational speed of the pulley 28,28′, 28″). The steps of activating and deactivating the pulley assistmechanism 30, 30′, 30″ may be performed by a controller/ECU 154, 154′,154″ adapted to control the output of one or more electric powersupplies (not shown), which may be electrically connected to the wirecoil 126, 126′, 126″ of the electromagnetic and/or the electricalwindings 68, 68′, 68″ of the stator assembly stator assembly 58, 58′,58″.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.These antecedent recitations should be interpreted to cover anycombination in which the inventive novelty exercises its utility. Manymodifications and variations of the present invention are possible inlight of the above teachings and may be practiced otherwise than asspecifically described while within the scope of the appended claims. Inaddition, the steps of the method set forth herein may be practiced in adifferent order than that listed herein without departing from the scopeof the appended claims.

What is claimed is:
 1. An electrically and mechanically drivenautomotive accessory, comprising: a housing; a shaft rotatably supportedin said housing, said shaft extending along a longitudinal axis betweenan input end and an output end; an electric motor comprising a statorassembly and a rotating assembly that is rotatable relative to saidstator assembly, said electric motor being configured to create aprimary torque flow path when said electric motor is activated; saidstator assembly fixedly mounted to said housing; said rotating assemblyfixedly mounted to said shaft such that said rotating assembly rotateswith said shaft; a pulley rotatably supported on said input end of saidshaft such that said pulley is rotatable relative to said shaft and saidrotating assembly; and a pulley assist mechanism including a pluralityof circumferentially spaced teeth nested with a conductive body, a rotorbody fixedly mounted to said shaft, and an electromagnet configured toinduce a magnetic field between said circumferentially spaced teeth,said rotor body, and said pulley to create a secondary torque flow pathbetween said pulley and said rotor body when said electromagnet isactivated, wherein said circumferentially spaced teeth are made of afirst material and said conductive body is made of a second material,wherein said first material is ferromagnetic and has a higher magneticflux density than said second material, and wherein said second materialhas a higher electrical conductivity than said first material, whereinsaid conductive body is fixed to said pulley and wherein saidcircumferentially spaced teeth are part of said pulley and extend into aplurality of openings in said conductive body, and wherein said rotorbody includes a plurality of circumferentially spaced ribs that generatea change in magnetic flux in said circumferentially spaced teeth andinduce an electric current in said conductive body when said pulleyrotates at a different speed than said rotor body.
 2. The electricallyand mechanically driven automotive accessory set forth in claim 1,wherein said plurality of circumferentially spaced teeth and saidplurality of circumferentially spaced ribs extend lengthwise in aplurality of radial directions transverse to said longitudinal axis. 3.The electrically and mechanically driven automotive accessory set forthin claim 1, wherein said first material is steel and said secondmaterial is aluminum or copper.
 4. The electrically and mechanicallydriven automotive accessory set forth in claim 1, further comprising: astationary backing member that is fixedly mounted to said housing andsupports said electromagnet of said pulley assist mechanism.
 5. Theelectrically and mechanically driven automotive accessory set forth inclaim 4, wherein said stationary backing member is made of a ferrousmetal material such that said electromagnet induces a magnetic loop inportions of said rotor body, said stationary backing member, and saidpulley.
 6. The electrically and mechanically driven automotive accessoryset forth in claim 1, wherein said housing includes a tubular portionthat receives said shaft and wherein said stator assembly is mounted tosaid tubular portion of said housing.
 7. The electrically andmechanically driven automotive accessory set forth in claim 6, whereinsaid pulley is supported by a shaft bearing assembly that is positionedradially between said shaft and said tubular portion of said housing. 8.The electrically and mechanically driven automotive accessory set forthin claim 1, wherein said pulley is configured to be driven by a belt andincludes a belt contact surface.
 9. The electrically and mechanicallydriven automotive accessory set forth in claim 1, further comprising: animpeller fixedly mounted to said output end of said shaft.
 10. Theelectrically and mechanically driven automotive accessory set forth inclaim 1, wherein said stator assembly includes stator plates that arefixedly mounted to said housing and support electrical windings andwherein said rotating assembly is disposed radially outwards of saidstator plates and includes permanent magnets fixedly mounted to arotating backing member that is rotatably fixed to said shaft by saidrotor body.